1. Field of the Invention
The present invention relates to a stereoscopic image forming apparatus, stereoscopic image forming method, stereoscopic image forming system and stereoscopic image forming program that can be suitably applied to formation of a stereoscopic image.
2. Description of the Related Art
Conventionally, the integral photography and the three-dimensional lenticular sheet image system are known as methods for forming a stereoscopic image (Okoshi, T. 1976, “Three-dimensional imaging techniques”, New York: Academic Press).
Such stereoscopic image forming methods are based on the photography. For example, in the method using the three-dimensional lenticular sheet image system, a three-dimensional lenticular sheet image is formed by shooting a subject from a plurality of different viewpoints to acquire respective images and printing these images on one photographic plate through a lenticular sheet. The conventional stereoscopic image forming method has the following disadvantages (1) to (3):
(1) An elaborate and large-scale shooting apparatus such as a multi-lens camera is required since images of a subject shot from multiple viewpoints are required;
(2) Similarly, an elaborate, large-scale printing apparatus is required for forming a stereoscopic image; and
(3) Specific adjustment and skill are required in shooting and printing even with the use of those elaborate, large-scale shooting and printing apparatuses.
To overcome the above disadvantages, a method has been proposed which comprises shooting a subject from two viewpoints at the right and left by a camera to which is mounted a stereophotographing adapter to acquire a pair of stereo images, and synthesizing a stereoscopic image from the pair of stereo images through electronic interpolation. This method, however, has a problem of requiring the stereophotographing adapter not required by normal shooting.
It is therefore ideal to acquire multiple viewpoint images from one image to form a stereoscopic image. An example of this method to obtain multiple viewpoint images from one image would comprise cutting out a subject region from the background in an image, and displacing a background image and a subject image by a predetermined parallax to synthesize a stereoscopic image when multiple viewpoint images are generated so that a user can feel as if the cutout subject region were coming up close when viewing the image with the lenticular sheet superposed on the image.
However, an apparatus that implements the above conventional method requires a large image memory capacity because multiple viewpoint images are temporarily generated from one image and thereafter a three-dimensional striped image is synthesized. Moreover, much time is required to synthesize the stereoscopic image, which must be reduced.